The world is full of the most mysterious and secret places. These are locations all around the world that we either don't know anything or about or, quite simply, are afraid to venture any further!

There are so many unexplained phenomena... who built some buildings... who created those statues... why do planes and ships disappear here... why do radios not work in some places... the list goes on and on.

In addition, there has often been so much uncertainty about these places. It is understandable, of course. After all, who is really brave enough to fly into the Bermuda Triangle just on a dare?

As we said, there are several such places all around the world and we couldn't possibly write about them all.

Nevertheless, click on "Slideshow" above, check out the following most mysterious places in the world... and tell us what you think...

Stonehenge is surely Britain's greatest national icon, symbolizing mystery, power and endurance. Its original purpose is unclear to us but some have speculated it was a temple made for the worship of ancient Earth (pagan?) deities. It has also been called an astronomical observatory for marking significant events on a prehistoric calendar. Others claim it was a sacred site for the burial of high-ranking citizens from societies of long ago. While we can't say with any degree of certainty what it was for, we can say it wasn't constructed for any casual purpose. Only something very important to the ancients would have been worth the effort and investment that it took to construct Stonehenge.

The Nazca Lines are the most outstanding group of geoglyphs in the world. Etched in the surface of the Peruvian desert, patterns outlining about 300 hundred figures, animals and birds, made of straight lines and geometric shapes... are visible only from the air! The massive-scaled geoglyphs also include stylized human-like forms. The fact that the lines, believed by some to be as old as 200BC, can only truly be appreciated from the air, has left generations mystified, as to how these could actually have been constructed and... just what they were meant for!

It is one of the most isolated islands in the world but 1200 years ago a double-hulled canoe filled with seafarers from a distant culture landed upon its shores. Over the centuries, a remarkable society developed in isolation on the island – on Easter Island. For reasons still unknown they began carving giant statues out of volcanic rock. These monuments, known as "moai" are some of the most incredible ancient relics ever discovered. The people of Easter Island called themselves the Rapa Nui. Science has learned much about the enigma of Easter Island and has put to rest some of the more bizarre theories but questions and controversies remain.

Deep within the jungles of Mexico and Guatemala and extending into the limestone shelf of the Yucatan peninsula lie mysterious temples and Mayan pyramids. The Mayan civilization was one of the most baffling ancient civilizations of all time. Until now, no one is certain who the Mayan were, how they lived and the reason behind the sudden collapse of their civilization.

The city of Xinjiang (Mogui Cheng) is also called the Wuerhe Windy City. Why? Well... about 100 kilometers to Karamay, the Demon City, as it is also called, is in the Wuerhe mining site, in the lower reaches of the Jiamu River. In the outlying Gobi Desert, there are numerous unexplained criss-crossing earthen mounds in different heights, like ancient castles. It is said that screaming and shouting sounds can be heard at night when the wind passes through them. Indeed, sometimes even the cries of monsters and wolves can be heard.

Although the archaeological discovery of Machu Picchu came nearly a hundred years ago, historians are still unsure of the function of this ancient Inca citadel. The Incans had no system of writing and left no written records and archaeologists have been left to piece together bits of evidence as to why Machu Picchu was built, what purpose it served and why it was so quickly vacated.